There have been developed so called blind setting rivets for securing sheet metal work parts or the like without requiring access to both sides of the parts. It is common practice to utilize a blind setting rivet assembly which includes a sleeve with an enlarged head and bore therethrough and a mandrel extending through the bore with an enlarged portion for upsetting the sleeve. This prior art device requires that holes be provided through the work so that the assembly may be inserted therethrough, followed by a retractive force applied to the mandrel causing the inner region of the sleeve to radially expand. The mandrel typically includes a weakened portion of generally annular reduced cross-sectional area so that the upper portions of the shank will fracture and disassociate from the lower portions. Self-drilling blind setting rivets of this type are not generally available since the mandrel must be positively rotated by the power tool for the drilling operation and must transmit torque through the weakened portion to a drilling tip. With some materials to be fabricated, the weakened portion of the shank does not permit sufficient torque to be transmitted to the drilling tip without premature shearing at the weakened portion which has been variously provided as by notching, peripheral grooving, etc.